RSM_MEMSEG_EXPORT_CREATE(3RSM) Remote Shared Memory Library Functions


NAME


rsm_memseg_export_create, rsm_memseg_export_destroy,
rsm_memseg_export_rebind - resource allocation and management functions
for export memory segments

SYNOPSIS


cc [ flag... ] file... -lrsm [ library... ]
#include <rsmapi.h>

int rsm_memseg_export_create(
rsmapi_controller_handle_t controller,
rsm_memseg_export_handle_t *memseg, void *vaddr,
size_t length, uint_t flags);


int rsm_memseg_export_destroy(
rsm_memseg_export_handle_t memseg);


int rsm_memseg_export_rebind(
rsm_memseg_export_handle_t memseg,
void *vaddr, offset_t off, size_t length);


DESCRIPTION


The rsm_memseg_export_create(), rsm_memseg_export_destroy(), and
rsm_memseg_export_rebind() functions provide for allocation and
management of resources supporting export memory segments. Exporting a
memory segment involves the application allocating memory in its virtual
address space through the System V shared memory interface or normal
operating system memory allocation functions. This is followed by the
calls to create the export segment and bind physical pages to back to
allocated virtual address space.


The rsm_memseg_export_create() creates a new memory segment. Physical
memory pages are allocated and are associated with the segment. The
segment lifetime is the same as the lifetime of the creating process or
until a destroy operation is performed. The controller argument is the
controller handle obtained from a prior call to
rsm_get_controller(3RSM). The export memory segment handle is obtained
through the memseg argument for use in subsequent operations. The vaddr
argument specifies the process virtual address for the segment. It must
be aligned according to the controller page size attribute. The length
argument specifies the size of the segment in bytes and must be in
multiples of the controller page size. The flags argument is a bitmask
of flags. Possible values are:

RSM_ALLOW_REBIND
Unbind and rebind is allowed on the segment
during its lifetime.


RSM_CREATE_SEG_DONTWAIT
The RSMAPI segment create operations
rsm_memseg_export_create() and
rsm_memseg_export_publish(3RSM) should not
block for resources and return
RSMERR_INSUFFICIENT_RESOURCES to indicate
resource shortage.


RSM_LOCK_OPS
This segment can be used for lock operations.


The rsm_memseg_export_destroy() function deallocates the physical memory
pages associated with the segment and disconnects all importers of the
segment. The memseg argument is the export memory segment handle
obtained by a call to rsm_memseg_export_create().


The rsm_memseg_export_rebind() function releases the current backing
pages associated with the segment and allocates new physical memory
pages. This operation is transparent to the importers of the segment. It
is the responsibility of the application to prevent data access to the
export segment until the rebind operation has completed. Segment data
access during rebind does not cause a system failure but data content
results are undefined. The memseg argument is the export segment handle
pointer obtained from rsm_memseg_export_create(). The vaddr argument must
be aligned with respect to the page size attribute of the controller. The
length argument modulo controller page size must be 0. The off argument
is currently unused.

RETURN VALUES


Upon successful completion, these functions return 0. Otherwise, an
error value is returned to indicate the error.

ERRORS


The rsm_memseg_export_create(), rsm_memseg_export_destroy(), and
rsm_memseg_export_rebind() functions can return the following errors:

RSMERR_BAD_SEG_HNDL
Invalid segment handle.


The rsm_memseg_export_create() and rsm_memseg_export_rebind() functions
can return the following errors:

RSMERR_BAD_CTLR_HNDL

Invalid controller handle.


RSMERR_CTLR_NOT_PRESENT

Controller not present.


RSMERR_BAD_LENGTH

Length zero or length exceeds controller limits.


RSMERR_BAD_ADDR

Invalid address.


RSMERR_INSUFFICIENT_MEM

Insufficient memory.


RSMERR_INSUFFICIENT_RESOURCES

Insufficient resources.


RSMERR_PERM_DENIED

Permission denied.


RSMERR_NOT_CREATOR

Not creator of segment.


RSMERR_REBIND_NOT_ALLOWED

Rebind not allowed.


The rsm_memseg_export_create() function can return the following errors:

RSMERR_BAD_MEM_ALIGNMENT
The address is not aligned on a page
boundary.


The rsm_memseg_export_rebind() function can return the following errors:

RSMERR_INTERRUPTED
The operation was interrupted by a signal.


The rsm_memseg_export_destroy() function can return the following errors:

RSMERR_POLLFD_IN_USE
Poll file descriptor in use.


USAGE


Exporting a memory segment involves the application allocating memory in
its virtual address space through the System V Shared Memory interface or
other normal operating system memory allocation methods such as valloc()
( see malloc(3C)) or mmap(2). Memory for a file mapped with mmap() must
be mapped MAP_PRIVATE.

ATTRIBUTES


See attributes(5) for descriptions of the following attributes:


+--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-----------------+
|Interface Stability | Unstable |
+--------------------+-----------------+
|MT-Level | MT-Safe |
+--------------------+-----------------+

SEE ALSO


rsm_get_controller(3RSM), rsm_memseg_export_publish(3RSM), attributes(5)


April 8, 2003 RSM_MEMSEG_EXPORT_CREATE(3RSM)